diff options
Diffstat (limited to 'shell')
| -rw-r--r-- | shell/hush.c | 52 |
1 files changed, 34 insertions, 18 deletions
diff --git a/shell/hush.c b/shell/hush.c index f29c985ad..a8f7237d5 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -6506,9 +6506,11 @@ static NOINLINE int expand_one_var(o_string *output, int n, * Word is expanded to produce a glob pattern. * Then var's value is matched to it and matching part removed. */ -//FIXME: ${x#...${...}...} -//should evaluate inner ${...} even if x is "" and no shrinking of it is possible - -//inner ${...} may have side effects! + /* bash compat: if x is "" and no shrinking of it is possible, + * inner ${...} is not evaluated. Example: + * unset b; : ${a%${b=B}}; echo $b + * assignment b=B only happens if $a is not "". + */ if (val && val[0]) { char *t; char *exp_exp_word; @@ -6547,7 +6549,12 @@ static NOINLINE int expand_one_var(o_string *output, int n, * and if // is used, it is encoded as \: * var\pattern<SPECIAL_VAR_SYMBOL>repl<SPECIAL_VAR_SYMBOL> */ - if (val && val[0]) { + /* bash compat: if var is "", both pattern and repl + * are still evaluated, if it is unset, then not: + * unset b; a=; : ${a/z/${b=3}}; echo $b # b=3 + * unset b; unset a; : ${a/z/${b=3}}; echo $b # b not set + */ + if (val /*&& val[0]*/) { /* pattern uses non-standard expansion. * repl should be unbackslashed and globbed * by the usual expansion rules: @@ -6583,8 +6590,9 @@ static NOINLINE int expand_one_var(o_string *output, int n, free(pattern); free(repl); } else { - /* Empty variable always gives nothing */ - // "v=''; echo ${v/*/w}" prints "", not "w" + /* Unset variable always gives nothing */ + // a=; echo ${a/*/w} # "w" + // unset a; echo ${a/*/w} # "" /* Just skip "replace" part */ *p++ = SPECIAL_VAR_SYMBOL; p = strchr(p, SPECIAL_VAR_SYMBOL); @@ -6599,40 +6607,48 @@ static NOINLINE int expand_one_var(o_string *output, int n, * var:N<SPECIAL_VAR_SYMBOL>M<SPECIAL_VAR_SYMBOL> */ arith_t beg, len; + unsigned vallen; const char *errmsg; beg = expand_and_evaluate_arith(exp_word, &errmsg); if (errmsg) - goto arith_err; + goto empty_result; debug_printf_varexp("beg:'%s'=%lld\n", exp_word, (long long)beg); *p++ = SPECIAL_VAR_SYMBOL; exp_word = p; p = strchr(p, SPECIAL_VAR_SYMBOL); *p = '\0'; - len = expand_and_evaluate_arith(exp_word, &errmsg); - if (errmsg) - goto arith_err; - debug_printf_varexp("len:'%s'=%lld\n", exp_word, (long long)len); + vallen = strlen(val); if (beg < 0) { /* negative beg counts from the end */ - beg = (arith_t)strlen(val) + beg; - if (beg < 0) /* ${v: -999999} is "" */ - beg = len = 0; + beg = (arith_t)vallen + beg; } + /* If expansion will be empty, do not even evaluate len */ + if (!val || beg < 0 || beg > vallen) { + /* Why > vallen, not >=? bash: + * unset b; a=ab; : ${a:2:${b=3}}; echo $b # "", b=3 (!!!) + * unset b; a=a; : ${a:2:${b=3}}; echo $b # "", b not set + */ + goto empty_result; + } + len = expand_and_evaluate_arith(exp_word, &errmsg); + if (errmsg) + goto empty_result; + debug_printf_varexp("len:'%s'=%lld\n", exp_word, (long long)len); debug_printf_varexp("from val:'%s'\n", val); if (len < 0) { /* in bash, len=-n means strlen()-n */ - len = (arith_t)strlen(val) - beg + len; + len = (arith_t)vallen - beg + len; if (len < 0) /* bash compat */ msg_and_die_if_script("%s: substring expression < 0", var); } - if (len <= 0 || !val || beg >= strlen(val)) { - arith_err: + if (len <= 0 || !val /*|| beg >= vallen*/) { + empty_result: val = NULL; } else { /* Paranoia. What if user entered 9999999999999 * which fits in arith_t but not int? */ - if (len >= INT_MAX) + if (len > INT_MAX) len = INT_MAX; val = to_be_freed = xstrndup(val + beg, len); } |